Morning sickness could well prevent the Duchesss of Cambridge from coming to Malta but a decision by the Royal household will only be made tomorrow.

The uncertainty has left the government without an official confirmation of who will replace her if she cannot make it.

Her brother-in-law Prince Harry, who turned 30 yesterday, has been mentioned as possibly taking her place, but government sources said the Royal household had not yet indicated a replacement.

She was expected to be the guest of honour for the 50th anniversary Independence celebrations over the weekend, arriving on Saturday and leaving the following day.

It was to be her first solo foreign engagement representing the British royal family.

She suffers from hyperemesis gravidarum, which causes severe dehydration as a result of extreme morning sickness.

Prince Harry yesterday postponed a 30th birthday bash because of Kate’s ailment.

Prince William and the Duchess of Cambridge had been involved in the planning of the intimate party for selected friends and family but Prince Harry decided to put it off.

The party was to have been held at Kensington Palace.